From 1b180d2f15e9b726e6e9dde5601f41fa48c1c044 Mon Sep 17 00:00:00 2001 From: Christian Cunningham Date: Mon, 3 Jan 2022 20:10:10 -0800 Subject: Ensured Aligned Mutexes --- later/schedule.S | 58 +++++++++++++++++++++++++ later/schedule.c | 83 +++++++++++++++++++++++++++++++++++ later/schedule.flat.c | 32 ++++++++++++++ later/schedule.h | 43 ++++++++++++++++++ later/schedule.ll.c | 13 ++++++ later/schedule.q.c | 118 ++++++++++++++++++++++++++++++++++++++++++++++++++ 6 files changed, 347 insertions(+) create mode 100644 later/schedule.S create mode 100644 later/schedule.c create mode 100644 later/schedule.flat.c create mode 100644 later/schedule.h create mode 100644 later/schedule.ll.c create mode 100644 later/schedule.q.c (limited to 'later') diff --git a/later/schedule.S b/later/schedule.S new file mode 100644 index 0000000..1811c7c --- /dev/null +++ b/later/schedule.S @@ -0,0 +1,58 @@ +.section .text +.globl preserveregs +preserveregs: + str r4, [r0, #0x10] + str r5, [r0, #0x14] + str r6, [r0, #0x18] + str r7, [r0, #0x1c] + str r8, [r0, #0x20] + str r9, [r0, #0x24] + str r10, [r0, #0x28] + str r11, [r0, #0x2c] + bx lr + +.globl restoreregs +restoreregs: + ldr r4, [r0, #0x10] + ldr r5, [r0, #0x14] + ldr r6, [r0, #0x18] + ldr r7, [r0, #0x1c] + ldr r8, [r0, #0x20] + ldr r9, [r0, #0x24] + ldr r10, [r0, #0x28] + ldr r11, [r0, #0x2c] + bx lr + +.globl exetask +exetask: + push {r0, r4, r5, r6, r7, r8, r9, r10, r11, lr} + // Restore registers from context switch + ldr r4, [r0, #0x10] + ldr r5, [r0, #0x14] + ldr r6, [r0, #0x18] + ldr r7, [r0, #0x1c] + ldr r8, [r0, #0x20] + ldr r9, [r0, #0x24] + ldr r10, [r0, #0x28] + ldr r11, [r0, #0x2c] + + // Preserve system stack + ldr r1, =msp + str sp, [r1] + // Setup task's stack + ldr sp, [r0, #0x34] + // Switch to task + ldr lr, [r0, #0x3c] + blx lr + // Restore system stack + ldr r1, =msp + ldr sp, [r1] + pop {r0, r4, r5, r6, r7, r8, r9, r10, r11, pc} + +.section .data +msp: + .space 4 +.section .data.stacks +.globl stacks +stacks: + .space 0x100000 diff --git a/later/schedule.c b/later/schedule.c new file mode 100644 index 0000000..8cf2780 --- /dev/null +++ b/later/schedule.c @@ -0,0 +1,83 @@ +#include "../sys/schedule.h" +#include "../lib/ll.h" +#include "../lib/q.h" + +#ifdef IGNORE +#ifdef FLAT +static struct Task* task_list[256]; + +static struct Scheduler scheduler = { + .tasks = task_list, +}; + +static unsigned int ntask_i = 0; + +void add_task(struct Task* t) +{ + scheduler.tasks[ntask_i] = t; + ntask_i += 1; + if (ntask_i > 256) { + ntask_i = 0; + } +} + +unsigned int get_task_length(void) +{ + return ntask_i; +} + +void execute_task(void) +{ + if (scheduler.tasks[ntask_i-1] != 0) + scheduler.tasks[ntask_i-1]->task(); +} +#elseif LL +static struct LL bl = { + .prev = 0, + .next = 0, +}; +static struct Scheduler scheduler = { + .tasks = &bl, +}; +#else +static struct Q_base bq = { + .next = 0, + .last = 0, +}; +static struct Scheduler scheduler = { + .tasks = &bq, +}; + +void add_task(struct Task* t) +{ + pushq(scheduler.tasks, t); +} + +unsigned int get_task_length(void) +{ + unsigned int length = 0; + if (scheduler.tasks->last == 0) + return length; + else if (scheduler.tasks->next == scheduler.tasks->last) + return 1; + else { + struct Q* q = scheduler.tasks->next; + length += 1; + while (q->next != 0) { + q = q->next; + length += 1; + } + return length; + } +} + +void execute_task(void) +{ + if (scheduler.tasks->last != 0) { + struct Task* tsk = (struct Task*)scheduler.tasks->next->data; + (tsk->task)(); + popq(scheduler.tasks); + } +} +#endif +#endif diff --git a/later/schedule.flat.c b/later/schedule.flat.c new file mode 100644 index 0000000..6eb0d14 --- /dev/null +++ b/later/schedule.flat.c @@ -0,0 +1,32 @@ +#ifdef FLAT + +#include "../sys/schedule.h" +static struct Task* task_list[256]; + +static struct Scheduler scheduler = { + .tasks = task_list, +}; + +static unsigned int ntask_i = 0; + +void add_task(struct Task* t) +{ + scheduler.tasks[ntask_i] = t; + ntask_i += 1; + if (ntask_i > 256) { + ntask_i = 0; + } +} + +unsigned int get_task_length(void) +{ + return ntask_i; +} + +void execute_task(void) +{ + if (scheduler.tasks[ntask_i-1] != 0) + scheduler.tasks[ntask_i-1]->task(); +} + +#endif diff --git a/later/schedule.h b/later/schedule.h new file mode 100644 index 0000000..77da7eb --- /dev/null +++ b/later/schedule.h @@ -0,0 +1,43 @@ +#ifndef SYS_SCHEDULE_H +#define SYS_SCHEDULE_H + +#define S_WAITING 0 +#define S_READY 1 + +#define STACK_SIZE 0x800 +struct Task { + unsigned char priority; + unsigned char status; + unsigned long pid; + void (*task)(void); + unsigned long reg[16]; + unsigned long stacki; + void* stack; +}; + +#ifdef FLAT +struct Scheduler { + unsigned long running_pid; + struct Task** tasks; +}; +#elseif LL +#include "../lib/ll.h" +struct Scheduler { + unsigned long running_pid; + struct LL* tasks; +}; +#else +#include "../lib/q.h" +struct Scheduler { + unsigned long running_pid; + struct Q_base* tasks; +}; +#endif + +void add_fxn(void (*task)(void), unsigned char priority); +unsigned char exists(void (*task)(void)); +void add_no_repeat(void (*task)(void), unsigned char priority); +unsigned int get_task_length(void); +void execute_task(void); + +#endif diff --git a/later/schedule.ll.c b/later/schedule.ll.c new file mode 100644 index 0000000..d9ab954 --- /dev/null +++ b/later/schedule.ll.c @@ -0,0 +1,13 @@ +#ifdef LL + +#include "../sys/schedule.h" +#include "../lib/ll.h" +static struct LL bl = { + .prev = 0, + .next = 0, +}; +static struct Scheduler scheduler = { + .tasks = &bl, +}; + +#endif diff --git a/later/schedule.q.c b/later/schedule.q.c new file mode 100644 index 0000000..4a5ff85 --- /dev/null +++ b/later/schedule.q.c @@ -0,0 +1,118 @@ +#if !(defined(LL) || defined(FLAT)) +#include "../sys/schedule.h" +#include "../lib/q.h" +#include "../lib/mem.h" +#include "../drivers/uart.h" + +extern void preserveregs(void*); +extern void restoreregs(void*); +extern void exetask(void*); + +static unsigned long next_pid = 3; +unsigned char table[256] = {0, }; + +static struct __attribute__((packed,align(4))) Q_base bq = { + .next = 0, + .last = 0, +}; +struct __attribute__((packed,align(4))) Scheduler scheduler = { + .running_pid = 0, + .tasks = &bq, +}; + +extern unsigned long __stacks_start; + +unsigned long getstack(void) +{ + for(unsigned int i = 0; i < 256; i++) { + if (table[i] == 0) { + table[i] = 1; + return i; + } + } + return -1; +} + +void add_fxn(void (*task)(void), unsigned char priority) +{ + struct Task* t = (struct Task*)malloc(sizeof(struct Task)); + // Allocate a stack frame and space for registers to be preserved on context switches + t->priority = priority; + t->task = task; + t->stacki = getstack(); + t->pid = next_pid; + next_pid += 1; + if(t->stacki > 256) + t->stack = 0; + else + t->stack = (void*)(__stacks_start + STACK_SIZE*t->stacki); + t->status = S_READY; + for(unsigned char i = 0; i < 13; i++) + t->reg[i] = 0; + t->reg[13] = (unsigned long)t->stack; + t->reg[14] = 0; // LR + t->reg[15] = (unsigned long)task; // PC + pushq(scheduler.tasks, t); +} + +unsigned char exists(void (*task)(void)) +{ + if (scheduler.tasks->next == 0) + return 0; + struct Q* q = scheduler.tasks->next; + while (q != 0) { + struct Task* t = q->data; + if (t->task == task) + return 1; + q = q->next; + } + return 0; +} + +void add_no_repeat(void (*task)(void), unsigned char priority) +{ + if (!(exists(task))) + add_fxn(task, priority); +} + +unsigned int get_task_length(void) +{ + unsigned int length = 0; + if (scheduler.tasks->last == 0) + return length; + else if (scheduler.tasks->next == scheduler.tasks->last) + return 1; + else { + struct Q* q = scheduler.tasks->next; + length += 1; + while (q->next != 0) { + q = q->next; + length += 1; + } + return length; + } +} +void execute_task(void) +{ + // Preserve Current Running PID's Data + if (scheduler.tasks->last != 0) { + struct Q* q = (struct Q*)scheduler.tasks->next; + while (((struct Task*)q->data)->status == S_WAITING) { + q = q->next; + } + struct Task* tsk = (struct Task*)q->data; + // Restore registers + // Including program counter as the entry point + // Including allocated stack position + // Set lr to the return address to restore system stack + //preserveregs(tsk->reg); + //restoreregs(tsk->reg); + scheduler.running_pid = tsk->pid; + exetask(tsk->reg); + scheduler.running_pid = 0; + table[tsk->stacki] = 0; + popq(scheduler.tasks); + } +} + +#endif -- cgit v1.2.1